Using 1) flash-freezing and 2) large-format MAR imaging plate at beamline 7-1, resolution has been extended to 2.35 w from previous limit of 2.8 w. This 2.8 w data set was obtained from frozen crystals with resolution limited by the smaller MAR imaging plates. Freezing has eliminated the radiation damage plaguing earlier experiments. A wide range of cryosolvents and artificial mother liquors were examined. Replacement of ammonium sulfate/citrate buffer by lithium sulfate/acetate buffer was successful. This artificial mother liquor will be used for heavy atom soaks. After screening low-resolution data in the lab, the promising candidates will be brought to SSRL. The best candidate to date is CH3HgCl; single-site Cys mutants will also be utilized (native has no cysteines).